Once semiconductor wafers are prepared, a large number of process steps are still necessary to produce desired semiconductor integrated circuits. In general the steps can be grouped into four areas: Front End Processing, Back End Processing, Test, and Packaging.
Front End Processing refers to the initial steps in the fabrication. In this stage the actual semiconductor devices (e.g., transistors) are created. A typical front end (also referred to herein as “frontend”) process includes: preparation of the wafer surface, patterning and subsequent implantation of dopants to obtain desired electrical properties, growth or deposition of a gate dielectric, and growth or deposition of insulating materials to isolate neighboring devices.
Once the semiconductor devices have been created they must be interconnected to form the desired electrical circuits. This “Back End Processing” of the back end (also referred to herein as “backend”) involves depositing various layers of metal and insulating material in the desired pattern. Typically the metal layers consist of aluminum, copper, and the like. The insulating material may include SiO2, low-K materials, and the like. The various metal layers are interconnected by etching holes, called “vias”, in the insulating material and depositing metal (e.g., Tungsten) in them.
Once the Back End Processing has been completed, the semiconductor devices are subjected to a variety of electrical tests to determine if they function properly. Finally, the wafer is cut into individual die, which are then packaged in packages (e.g., ceramic or plastic packages) with pins or other connectors to other circuits, power sources, and the like.